This invention concerns an apparatus for coordinate positioning in general, and more particularly, for positioning of wafers, which can be used in probe tests of different states of readiness of semiconductor components and integrated circuits with quick and accurate sequence.
A known apparatus for coordinate positioning is composed of two stepping motors, connected by means of rigid clutches to lead screws, onto which are screwed-on cut nuts. One of the nuts is fastened to a body carrying a mechanism for vertical lifting of the working table. The first lead screw is seated on both sides in a cradle. The body is disposed onto a base by means of legs. The other cut nut is attached to the cradle in cantilever, while the respective lead screw is seated in two columns. The second stepping motor is attached to one of these two columns.
A disadvantage of the known apparatus is the comparatively great error due to reverse motion in the displacement of the body with the cradle, as well as the necessity of having to balance the system, a requirement which results in irregular wear.